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Oligotrophication of Lake Balaton over a 20-year period and its implications for the relationship between phytoplankton and zooplankton biomass
- Source :
- Hydrobiologia. 847:3999-4013
- Publication Year :
- 2020
- Publisher :
- Springer Science and Business Media LLC, 2020.
-
Abstract
- Lake Balaton, the largest lake in Central Europe, underwent severe eutrophication from the 1960s to the 1990s, due to phosphorus loadings from external anthropogenic sources. The subsequent and complex eutrophication control and lake restoration program resulted in a significant decrease in the external phosphorus loading to the lake. Consequently, Lake Balaton has been returning to its former meso-eutrophic character. In this paper, we explore the long-term dynamics of chlorophyll a (Chl a) concentration, a proxy for phytoplankton biomass, and zooplankton biomass in Lake Balaton during its re-oligotrophication period from 2001 to 2017, and attempt to draw some conclusions on the subsequent changes in the fish stock. We found a proportional decrease in zooplankton and phytoplankton biomasses at moderate phytoplankton levels. However, below a certain phytoplankton concentration (−1 Chl a), the decrease in phytoplankton biomass was not coupled with a further decline in zooplankton biomass because the fraction of small phytoplankton, edible for zooplankton, showed a much smaller decrease in biomass compared with large non-edible phytoplankton. Thus, improvements in water quality (i.e., reduced nutrient loading), partly via concomitant changes in the phytoplankton size distribution, did not cause a large difference in the fish stock in this shallow lake.
- Subjects :
- 0106 biological sciences
Chlorophyll a
010604 marine biology & hydrobiology
Zooplankton biomass
Aquatic Science
Fish stock
010603 evolutionary biology
01 natural sciences
Zooplankton
chemistry.chemical_compound
Nutrient
Oceanography
chemistry
Phytoplankton
Environmental science
Water quality
Eutrophication
Subjects
Details
- ISSN :
- 15735117 and 00188158
- Volume :
- 847
- Database :
- OpenAIRE
- Journal :
- Hydrobiologia
- Accession number :
- edsair.doi...........23f052c782aa7d68aa289e41a6ee2456